Collect and display AsyncJS processing time and dynamic generation time (#278)

Experiments some new JS API in React for prepare the next refactoring of Navigate (#277 but not active for the moment)

Create a new API, JSModule, for extract algorithms in Java side to JS side (server side and/or client side), and let them editable by the admin without change the Java code. getIdFromFilename() will be the first to be moved to Javascript side.

Not some bigger newer tools, but a real build process with downloadable packages. A big refactoring with the end of old-style Groovy pages, a new access to for code Gson, new dynamic class instantiations…